The present invention relates generally to earth working tools such as tillage tools and plows, and more particularly to a spring trip release structure for such an earth working tool.
One of the problems with earth working tools such as plows, cultivators, and other tillage tools is that when the tool hits a hard object, such as a rock, quite often a portion of the tool itself or its connecting structure breaks. Much attention has been given to this problem, and the most widely accepted solution has been the use of a structure which allows the tool to pivot rearwardly and somewhat upwardly as is shown in U.S. Pat. Nos. 3,098,529; 3,431,982 and 3,493,055 for example. Springs are also provided on such units for automatically returning the tillage tool to its original earth working position after it has passed the obstruction.
The problem has been that quite often the tool itself simply does not travel high enough when tripped to completely avoid the obstruction and prevent breakage. This is especially true on the frequent occassions when a rock is pulled upwardly from the ground by the tillage tools so that it is higher than when it was originally encountered. Consequently, there is a need to move the earth working tool as high as possible and as soon as possible when the tool meets an obstruction, and then return the tool as quickly as possible back in to its proper earth working position.